Render is completely transparent
The issue you are having is that the layers you have set your Render Layers to are completely blank in front of the camera. You need to add the correct layers in your Render Layers settings.




The reason this was rendering in the viewport, is you had all of the layers selected to display in your viewport, while those layers were not enabled in the final render.



You may want to disable the compositing stage to get ride of the video overlay :



to keep the compositing and just eliminate the video overlay change the compositing nodes as this :